Sulfur modified asphalt for warm mix applications

ABSTRACT

Disclosed herein are an asphalt concrete mixture, an asphalt binder composition, and methods of preparing the related compositions. The asphalt binder compositions include a polyphosphoric acid, a macromolecular polymer having a saturated backbone with macromolecular modifications, sulfur, and non-surfactant additives based on wax chemistry. The compositions are capable of being performance graded and being used in warm mix asphalt applications.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a divisional application and claims priority fromU.S. Non-provisional patent application Ser. No. 12/938,984, filed Nov.3, 2010. For purposes of United States patent practice, this applicationincorporates the contents of the Non-provisional Application byreference in its entirety.

FIELD OF THE INVENTION

Disclosed herein are an asphalt concrete mixture, an asphalt bindercomposition, and methods of preparing the asphalt concrete mixture.

BACKGROUND OF THE INVENTION

As modern commerce depends on reliable and cost-effective methods fordelivering products from suppliers to users, the availability of durableand reliable highways, roads and other support surfaces for vehicles isvital for sustaining a modern economy. To provide better supportsurfaces, highways, roads, and sidewalks are commonly paved with a layeror mat of asphalt concrete that is laid over the surface of thesub-base. Asphalt is preferred over Portland Concrete cement to pavedroads because it is less expensive and very durable.

Asphalts are essentially mixtures of bitumen, as binder, with aggregate,in particular mineral filler, fine aggregates, and coarse aggregates.There are many different types of asphalts available and theircharacteristics can vary quite significantly. The design of asphalts forbituminous paving application is a complex process of selecting andproportioning materials to obtain the desired properties in the finishedconstruction while minimize undesirable characteristics.

In evaluating and adjusting mix designs, the aggregate gradation and thebinder content in the final mix design are balanced between thestability and durability requirements for the intended use. The finalgoal of mix design is to achieve a balance among all of the desiredproperties. Binders and various polymers have been investigated forreaching similar goals, and other modifications have been studied.

Unsaturated thermoplastic elastomers like styrene-butadiene-styrene(SBS) block copolymers, linear copolymers, diblock copolymers and radialcopolymers are polymers used for asphalt modification. They enhance theelastic recovery capacities of asphalt and, therefore, its resistance topermanent deformations. However, unsaturated elastomeric polymers arequite expensive and are subjected to degradation when exposed toatmospheric agents and mechanical stress. This can result in asignificant cost increase for the product. While SBS is recognized forperformance benefits, research has focused on most cost effectivemodifiers in exchange for sacrificing superior performance.

Olefinic polymers have been investigated for use as modifiers. They areavailable in large quantities with different mechanical properties andat low cost. Polyethylene (PE) and polypropylene (PP) are plastomers.They bring a high rigidity (i.e., lack of elasticity, resistance tobending) to the product and significantly reduce deformations undertraffic load. Due to their non-polar nature, PE and PP suffer from thedrawback that they are almost completely immiscible with asphalt, andare thus limited in use.

Conventional asphalts often do not retain sufficient elasticity in useand, also, exhibit a plasticity range that is too narrow for use in manymodern applications such as road construction. The characteristics ofroad asphalts can be improved by incorporating into them anelastomeric-type polymer. There exists a wide variety of polymers thatcan be mixed with asphalt. Of these, SBS is a commonly used polymer inasphalt modification. The modified asphalts thus obtained commonly arereferred to variously as bitumen/polymer binders or asphalt/polymermixes. There is a need for a modification to hot mix asphalt concretemixes that would increase the resistance to permanent deformation whilemaintaining or decreasing the modulus of the mix at intermediatetemperatures without affecting the binder properties significantly.

The bituminous binders, even of the bitumen/polymer type, which areemployed at the present time in road applications often, do not have theoptimum characteristics at low enough polymer concentrations toconsistently meet the increasing structural and workability requirementsimposed on roadway structures and their construction. In order toachieve a given level of modified asphalt performance, various polymersare added at some prescribed concentration. Current practice is to addthe desired level of a single polymer, sometimes along with a reactantthat promotes cross-linking of the polymer molecules for compatibilityuntil the desired asphalt properties are met. This reactant typically issulfur in a form suitable for reacting.

Numerous approaches have been used to incorporate sulfur as acrosslinking agent into asphalt compositions in the past. Typically theloadings are from about 0 wt. % to about 5 wt. % of the polymer. Fornon-crosslinking application, typically approaches have been to addbetween 5-70 wt. % sulfur into asphalt and non-asphalt based binders toperform in asphalt pavement applications.

When added to bitumen at 140° C., sulfur is finely dispersed in bitumenas uniformly small particles; coagulation and settlement of sulfurparticles become noticeable after a few hours. Therefore, the sulfurextended asphalt (SEA) mixtures can be produced directly in the mixingplant just before the laying of the asphalt mixture. One major concernin handling sulfur-asphalt mix is the fear of the evolution of hydrogensulfide (H₂S) during production and laying. H₂S evolution starts attemperatures higher than 150° C., so that the application attemperatures up to 150° C. avoids pollution and safety problems.However, H₂S evolution starts well below 150° C., i.e. about 130° C.Moreover, below 120° C., neither the reaction of the asphalt and sulfurnor the cross-linking of the SBS/sulfur blend could take place.

A need exists for asphalt compositions that can be performance grade. Itwould be advantageous if the compositions could include materials, suchas sulfur, that enhance performance of the compositions, while beingrelatively inexpensive.

SUMMARY OF THE INVENTION

In view of the foregoing, asphalt concrete compositions, asphalt bindercompositions, and methods of preparing the compositions are provided asembodiments of the present invention. The asphalt binder compositionsgenerally include a polyphosphoric acid, a macromolecular polymer havinga saturated backbone with macromolecular modifications, sulfur, andnon-surfactant additives based on wax chemistry. In an aspect, thesulfur can be elemental sulfur or any form whether in powder form,slurry, or crystallized in the orthorhombic form. The binder can beadded to asphalt concrete to produce the asphalt concrete compositions.

An asphalt concrete composition having high sulfur load with improvedproperties relative to high temperature rotational viscosity without areduction in dynamic shear properties is provided as an embodiment ofthe present invention. In this embodiment, the asphalt concretecomposition includes a polyphosphoric acid a macromolecular polymerhaving a saturated backbone with macromolecular modifications, sulfur,non-surfactant additives based on wax chemistry, and an asphaltconcrete. Polyphosphoric acid can have the empirical formulaP_(q)H_(r)O_(s) in which q, r, and s are positive numbers such that q isgreater or equal to 2 and preferably ranges from 3 to 20. Any linearcompound of the empirical formula P_(q)H_(q+2)O_(3q+1) or polyphosphoricacids that can be polycondensation products formed from heating ofmetaphosphoric acid can be used in embodiments of the present invention.In an aspect, the sulfur can be elemental sulfur or any form whether inpowder form, slurry, or crystallized in the orthorhombic form. In anaspect, the asphalt concrete includes aggregate and bitumen.

The amounts of each component contained within the asphalt concretecomposition can be varied. The polyphosphoric acid can be present in anamount effective to provide increased stiffness at the lower mixingtemperatures. The macromolecular polymer can be present in an amounteffective to increase viscosity of the composition so that it can beused in warm mix applications. Any polymer with a saturated hydrocarbonbackbone, with or with reactive functionality can be used in embodimentsof the present invention. Polymers formed from the monomers of ethylene,propylene, acrylate, butyacrylates, butylenes, hexenes, octenes,acrylate, butyacrylates, butylenes, etc.; long chain branchedpolyolefins with octenes; polyolefins graft or/or block/or diblock/ortriblock polymers with maleic anhydride, fumarate and maleate esters,(meth)acrylate esters [e.g. glycidyl methacrylate and hydroxyethylmethacrylate] and (meth)acrylic acid; polyolefin elastomers containingreactive p-methylstyrene groups, such aspoly(isobutylene-co-p-methylstyrene) elastomers; or combinations thereofcan be used in embodiments of the present invention. The sulfur can bepresent in an amount effective to at least partially emulsify in thecomposition. The non-surfactant additives based on wax chemistry can bepresent in an amount effective to provide a lubricating effect on thecomposition.

As another embodiment of the present invention, a highly loadedsulfur-modified asphalt binder composition for use with asphalt concretefor improved properties relative to high temperature rotationalviscosity without a reduction in dynamic shear properties is provided.In this embodiment, the binder includes a polyphosphoric acid, amacromolecular polymer having a saturated backbone with macromolecularmodifications, non-surfactant additives based on wax chemistry, andsulfur. In an aspect, the sulfur can be elemental sulfur or any formwhether in powder form, slurry, or crystallized in the orthorhombicform.

The amounts of the components of the binder composition can vary. Forexample, the polyphosphoric acid is present in a range of about 0 wt. %to about 2.0 wt. % to provide increase stiffness at lower mixingtemperatures. As another example, the macromolecular polymer having asaturated backbone with macromolecular modifications is present in arange of about 0 wt. % to about 5 wt. % to increase elasticity of thebinder so that it can be used in warm mix applications. The sulfur ispresent in an amount effective to at least partially emulsify in thecomposition. The non-surfactant additives based on wax chemistry ispresent in an amount effective to provide a lubricating effect on thecomposition. Other suitable amounts of each component will be apparentto those of skill in the art and are to be considered within the scopeof the present invention.

Besides the compositional embodiments, methods of preparing the asphaltcomposition are also provided as embodiments of the present invention.In an embodiment, a method of preparing an asphalt concrete compositionhaving high sulfur load with improved properties relative to hightemperature rotational viscosity without a reduction in dynamic shearproperties is provided.

In an embodiment, a binder composition is prepared that includes apolyphosphoric acid, a macromolecular polymer having a saturatedbackbone with macromolecular modifications, non-surfactant additivesbased on wax chemistry, and sulfur. The polyphosphoric acid is presentin an amount effective to provide increase stiffness as lower mixingtemperatures. The macromolecular polymer is present in an amounteffective to increase elasticity of the composition. The non-surfactantadditives based on wax chemistry is present in an amount effective toprovide a lubricating effect on the composition. In an aspect, thesulfur can be elemental sulfur or any form whether in powder form,slurry, or crystallized in the orthorhombic form. The sulfur is presentin an amount effective to at least partially emulsify in thecomposition. Once the binder has been prepared, it is combined withasphalt concrete to produce the asphalt concrete composition. As withother embodiments, the asphalt concrete includes aggregate and bitumen.

As indicated previously, sulfur has been explored to modify asphalt byothers; however, sulfur-modified asphalt compositions have not able tobe Superpave® performance graded (PG). The unreacted sulfur in the pastattempts tended to cause embrittlement upon aging. Embodiments of thepresent invention include sulfur modified asphalt compositions that canperform as an asphalt binder in paving applications. The composition ofthe binder allows these materials to be performance graded and improvesthe grading of the asphalt over an unmodified control at both the hightemperature and low temperature regions, which significantly enhancesthe both low and higher temperature applications of these materials inthe pavement construction. The compositional embodiments of the presentinvention are compliant to super pave performance grades of asphalts andimproves the grading of the asphalt over an unmodified control at boththe high temperature and low temperature regions. The bindercompositions of the present invention can be used as a low costalternative to polymer modified binders in asphalt pavementapplications.

The present invention relates to a warm mix sulfur modified asphalt forwarm mix applications by modification of asphalt with sulfur,polyphosphoric acid (PPA), a polymer having saturated backbonemacromolecules with macromolecular modifications (co-polymer,ter-polymer, graft-block co or ter-polymer (random, alternating, block,graft-block that can contain reactive functionality)), asphalt, andvarious warm mix additives. The sulfur can be present in a range ofabout 5 wt. % to about 50 wt. %. The PPA can be present in a range ofabout 0 wt. % to about 2.0 wt. %. The polymer having saturated backbonemacromolecules can be present in a range of about 0 wt. % to about 5 wt.%. Asphalt can be present in a range of about 50 wt. % to about 90 wt.%.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features, aspects andadvantages of the invention, as well as others that will becomeapparent, are attained and can be understood in detail, more particulardescription of the invention briefly summarized above can be had byreference to the embodiments thereof that are illustrated in thedrawings that form a part of this specification. It is to be noted,however, that the appended drawings illustrate some embodiments of theinvention and are, therefore, not to be considered limiting of theinvention's scope, for the invention can admit to other equallyeffective embodiments.

FIG. 1 illustrates the Stroke Count (Passes) versus Depth for the BlendNo. 2 at 52° C. made in accordance with prior art embodiments.

FIG. 2 illustrates the Stroke Count (Passes) versus Depth for the BlendNo. 5 at 52° C. made in accordance with embodiments of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

It is desirable for asphalt concrete, including asphalt and aggregate,asphalt compositions for resurfacing asphalt concrete, and similarasphalt compositions to exhibit a certain number of specific mechanicalproperties to enable their use in various fields of application,especially when the asphalts are used as binders for superficial coats(road surfacing), as asphalt emulsions, or in industrial applications.As used herein, the term “asphalt” can be used interchangeably with“bitumen.” As used herein, “asphalt concrete” is generally asphalt usedas a binder with appropriate aggregate added, typically for use inroadways. The use of asphalt or asphalt emulsion binders surfacetreatment or as a very thin bituminous mix, or as a thicker structurallayer of bituminous mix in asphalt concrete, is enhanced if thesebinders possess the requisite properties such as desirable levels ofelasticity and plasticity.

The grades and characteristics of asphalt paving products are defined byvarious professional organizations, such as the Asphalt Institute. Forexample, Rolling Thin Film Oven (RTFO) and Pressure Aging Vessel (PAV)studies are used to simulate binder aging (hardening) characteristics.Dynamic Shear Rheometers (DSR) are used to measure binder properties athigh and intermediate temperatures. This is used to predict permanentdeformation or rutting and fatigue cracking. Industry custom uses theshort form RTFO DSR to indicate the temperature at which a sample willshow sufficient rutting resistance after rolling thin film oven (RTFO)aging (minimum rutting resistance as defined as a “G*·sin δ” over 2.20kPa and measured by a dynamic shear rheometer (DSR)). Fatigue crackingis a series of interconnecting cracks caused by failure of the asphaltconcrete surface under repeated traffic loading. Bending Beam Rheometers(BBR) are used to measure binder properties at low temperatures. Thesevalues predict thermal or low temperature cracking. Various industrystandards, such as the Superpave standard, exist for defining suchprocedures for these experiments and measurement.

Asphalt grading is given in accordance with accepted standards in theindustry, such as PG 64-22, where “PG” stands for Performance Grade and64 is related to the higher temperature in degrees Celsius and -22 isthe low temperature in degrees Celsius.

As indicated previously, asphalt concrete includes asphalt combined withaggregates in various rations, one exemplary ration being approximately95 parts by weight of aggregate to approximately 5 parts by weight ofliquid asphalt. The asphalt cement is used to bind together theaggregate material and limit its mobility when a load is applied. Theaggregate is usually a mixture of mineral filler, fine aggregates, andcoarse aggregates; the largest pieces of aggregate having a diameterequal to about ⅔ the thickness of the asphalt mat. The aggregate hascrushed particles to provide sharp edges in the gravel and stone that,when combined with the liquid asphalt, create an aggregate interlockthat improves the strength of the mat. The aggregate and liquid asphaltare heated and mixed to form an asphalt paving composition calledhot-mix asphalt (HMA).

Elastic modulus, which is sometimes called Young's modulus, is aproperty that is often used to determine if an asphalt composition issuitable for a particular application. Elastic modulus (E) can bedetermined for a solid material and represents a constant ratio ofstress and strain (a stiffness): E=stress/strain. A material is elasticif it is able to return to its original shape or size immediately afterbeing stretched or squeezed. Almost all materials are elastic to somedegree as long as the applied load does not cause it to deformpermanently. Thus, the “flexibility” of any object or structure dependson its elastic modulus and geometric shape. The modulus of elasticityfor a material is basically the slope of its stress-strain plot withinthe elastic range.

Asphalt has been the subject of exhaustive study to improvecharacteristics for use in paving. Various properties of asphalt aremanipulated to produce a product that has the appropriate frictionproperties, rut resistance, fatigue and low temperature crackingresistance, and viscosity. Rut resistance is resistance to longitudinalsurface depressions in the wheel paths. Rut resistance is resistance topermanent, longitudinal displacement of a localized area of the pavementsurface caused by traffic pushing against the pavement. Heavyhydrocarbon that can be derived from, without limitation, naturalasphalt (such as Gilsonite®), Trinidad Lake Asphalt, shale asphalt,bottoms from a solvent de-asphalting process, hard asphalt, blownasphalt, stiff refined asphalt, or a flux. Asphalt is usually the baseingredient for the primer and the binder. A primer can be asphalt,fibers (including but not limited to, mineral or cellulose), processingagent (including but not limited to, oligomeric wax, carboxylated,derivative of oligomeric wax, or low molecular weigh polyolefins),polymeric or elastomeric additive, or asphalt-derived. A primer melts tothe aggregate. Asphalt binders without polymers are referred to as“neat”.

The general field of the invention is the modification of asphalt byusing sulfur, saturated polymer having backbone macromolecules withmacromolecular modifications (co-polymer, ter-polymer, graft-block co orter-polymer (random, alternating, block, graft-block that can containreactive functionality)) 0-5 wt. %, Polyphosphoric acid and warm mixadditives. The warm mix additives can be non-surfactant additives basedon wax chemistry. The composition can be performance graded and used inwarm mix asphalt applications.

None of the previous techniques used the combination ofadditives/modifiers and developed a binder specifically for warm mixasphalt applications. More specifically to be able to compact asphaltfrom 30-70° F. below conventional asphalt mixtures and obtain equal orbetter performance at a reduced total raw material cost. The mixing ofsulfur under high shear in loadings from 20-50 wt. % produced a binderwith improved low temperature properties and reduced high temperatureviscosities. The combination of this binder containing saturatedbackbone macromolecules with macromolecular modifications (co-polymer,ter-polymer, graft-block co or ter-polymer (random, alternating, block,graft-block that can contain reactive functionality)), warm mixadditives, and/or PPA produced a novel compound with macromolecularmodified asphalt properties and warm mix binder at a reduced overall rawmaterial cost.

In view of the foregoing, asphalt concrete compositions, asphalt bindercompositions, and methods of preparing the compositions are provided asembodiments of the present invention. The asphalt binder compositionsgenerally include a polyphosphoric acid, a macromolecular polymer havinga saturated backbone with macromolecular modifications, non-surfactantadditives based on wax chemistry, and sulfur. In an aspect, the sulfurcan be elemental sulfur or any form whether in powder form, slurry, orcrystallized in the orthorhombic form. The binder can be added toasphalt concrete to produce the asphalt concrete compositions.

An asphalt concrete composition having high sulfur load with improvedproperties relative to high temperature rotational viscosity without areduction in dynamic shear properties is provided as an embodiment ofthe present invention. In this embodiment, the asphalt concretecomposition includes a polyphosphoric acid, a macromolecular polymerhaving a saturated backbone with macromolecular modifications,non-surfactant additives based on wax chemistry, sulfur, and an asphaltconcrete. Polyphosphoric acid can have the empirical formulaP_(q)H_(r)O_(s) in which q, r, and s are positive numbers such that q isgreater or equal to 2 and preferably ranges from 3-20. Any linearcompound of the empirical formula P_(q)H_(q+2)O_(3q+1) or polyphosphoricacids that can be polycondensation products formed from heating ofmetaphosphoric acid can be used in embodiments of the present invention.In an aspect, the sulfur can be elemental sulfur or any form whether inpowder form, slurry, or crystallized in the orthorhombic form. In anaspect, the asphalt concrete includes aggregate and bitumen.

The amounts of each component contained within the asphalt concretecomposition can be varied. The polyphosphoric acid can be present in anamount effective to provide increased stiffness at lower mixingtemperatures. The macromolecular polymer can be present in an amounteffective to increase elasticity of the composition so that it can beused in warm mix applications. Any polymer with a saturated hydrocarbonbackbone, with or with reactive functionality can be used in embodimentsof the present invention. Polymers formed from the monomers of ethylene,propylene, acrylate, butyacrylates, butylenes, hexenes, octenes,acrylate, butyacrylates, butylenes, etc.; long chain branchedpolyolefins with octenes; polyolefins graft or/or block/or diblock/ortriblock polymers with maleic anhydride, fumarate and maleate esters,(meth)acrylate esters [e.g. glycidyl methacrylate and hydroxyethylmethacrylate] and (meth)acrylic acid; polyolefin elastomers containingreactive p-methylstyrene groups, such aspoly(isobutylene-co-p-methylstyrene) elastomers; or combinations thereofcan be used in embodiments of the present invention. The non-surfactantadditives based on wax chemistry can be present in an amount effectiveto provide a lubricating effect on the compositions. The sulfur can bepresent in an amount effective to at least partially emulsify in thecomposition.

As another embodiment of the present invention, a highly loadedsulfur-modified asphalt binder composition for use with asphalt concretefor improved properties relative to high temperature rotationalviscosity without a reduction in dynamic shear properties is provided.In this embodiment, the binder includes a polyphosphoric acid, amacromolecular polymer having a saturated backbone with macromolecularmodifications, non-surfactant additives based on wax chemistry, andsulfur. In an aspect, the sulfur can be elemental sulfur or any formwhether in powder form, slurry, or crystallized in the orthorhombicform.

The amounts of the components of the asphalt composition and the bindercomposition can vary. For example, the polyphosphoric acid is present ina range of about 0 wt. % to about 2.0 wt. % to provide increasedstiffness at lower mixing temperatures. As another example, themacromolecular polymer having a saturated backbone with macromolecularmodifications is present in a range of about 0 wt. % to about 10 wt. %to increase elasticity of the binder so that it can be used in warm mixapplications. The non-surfactant additives based on wax chemistry can bepresent in an amount effective to provide a lubricating effect on thecomposition. In an aspect, the non-surfactant additives based on waxchemistry can be present in a range of about 0 wt. % to about 10 wt. %.The non-surfactant additives can include various warm mix additives. Thesulfur is present in an amount effective to at least partially emulsifyin the composition. In an aspect, the sulfur is present in loadingsranging from about 20 wt. % to about 50 wt. %. When there is asphaltconcrete present, the asphalt concrete can be present in a range ofabout 50 wt. % to about 90 wt. %. Other suitable amounts of eachcomponent will be apparent to those of skill in the art and are to beconsidered within the scope of the present invention.

Besides the compositional embodiments, methods of preparing the asphaltcomposition are also provided as embodiments of the present invention.In an embodiment, a method of preparing an asphalt concrete compositionhaving high sulfur load with improved properties relative to hightemperature rotational viscosity without a reduction in dynamic shearproperties is provided.

In an embodiment, a binder composition is prepared that includes apolyphosphoric acid, a macromolecular polymer having a saturatedbackbone with macromolecular modifications, and sulfur. In an aspect,the sulfur can be elemental sulfur or any form whether in powder form,slurry, or crystallized in the orthorhombic form. The polyphosphoricacid is present in an amount effective to provide increased stiffnessand lower mixing temperatures. The macromolecular polymer is present inan amount effective to increase elasticity of the composition so that itcan be used in warm mix applications. The non-surfactant additives basedon wax chemistry is present in an amount effective to provide alubricating effect on the composition. The sulfur is present in anamount effective to at least partially emulsify in the composition. Oncethe binder has been prepared, it is combined with asphalt concrete toproduce the asphalt concrete composition. As with other embodiments, theasphalt concrete includes aggregate and bitumen.

The compositional embodiments of the present invention are compliant tosuper pave performance grades of asphalts and improves the grading ofthe asphalt over an unmodified control at both the high temperature andlow temperature regions. The binder compositions of the presentinvention can be used as a low cost alternative to polymer modifiedbinders in asphalt pavement applications. The compositions of thepresent invention can be used in paving applications.

Embodiments of the present invention include sulfur modified asphaltcompositions that can perform as an asphalt binder in pavingapplications. The composition of the binder allows these materials to beperformance graded and improves the grading of the asphalt over anunmodified control at both the high temperature and low temperatureregions, which significantly enhances the applications in both low andhigher temperature ranges in the pavement construction industry in whichthe compositions of the present invention can be used.

As indicated previously, sulfur has been explored to modify asphalt byothers; however, sulfur-modified asphalt compositions have not able tobe super pave performance graded. The unreacted sulfur in the pastattempts tended to cause embrittlement upon aging. Embodiments of thepresent invention include sulfur modified asphalt compositions that canperform as an asphalt binder in paving applications.

In an aspect, the compositions of the present invention are PG graded.The performance grade of the compositions of the present invention canvary depending upon the amounts of the components that are present inthe compositions. For example, if the sulfur is present in an amount ofabout 20 wt. %, then the composition is PG graded as 64-34. An anotherexample, if the sulfur is present in an amount of about 50 wt. %, thenthe composition is PG graded as 64-28.

The components contained in compositions of the present inventionprovide the compositions with good physical properties, particularlywhen compared with conventional asphalt compositions. For example, in anaspect, the compositions of the present invention have a dynamic shearin a range of about 1,000 G*·sin δ to about 5,000 G*·sin δ at about 25°C. Besides the dynamic shear, the rotation viscosity is also reduced asa result of the components contained in the compositions of the presentinvention. In an aspect, the composition has a rotational viscosity in arange of about 0.100 Pa·sec to about 0.300 Pa·sec.

The types of macromolecular polymer having a saturated backbone withmacromolecular modifications can vary. For example, the macromolecularpolymer having a saturated backbone with macromolecular modificationscan include any polymer with a saturated hydrocarbon backbone, with orwith reactive functionality can be used in embodiments of the presentinvention. Polymers formed from the monomers of ethylene, propylene,acrylate, butyacrylates, butylenes, hexenes, octenes, acrylate,butyacrylates, butylenes, etc.; long chain branched polyolefins withoctenes; polyolefins graft or/or block/or diblock/or triblock polymerswith maleic anhydride, fumarate and maleate esters, (meth)acrylateesters [e.g. glycidyl methacrylate and hydroxyethyl methacrylate] and(meth)acrylic acid; polyolefin elastomers containing reactivep-methylstyrene groups, such as poly(isobutylene-co-p-methylstyrene)elastomers; or combinations thereof can be used in embodiments of thepresent invention. [Other suitable types of polymers that can be used inthe present invention will be apparent to those of skill in the art andare to be considered within the scope of the present invention.

The types of non-surfactant additives based on wax chemistry used inembodiments of the present invention can be varied depending on thedesired results. For example, examples of suitable non-surfactantadditives based on wax chemistry can include Sasobit® wax,Fischer-Tropsch wax, ceresin wax, montan wax, wax extracted from ligniteand brown coal, Ozocerite that is found in lignite beds, peat wax,paraffin wax, microcrystalline wax, Petroleum jelly, non-paraffin wax,natural wax, carnuba wax, bees wax, candelilla wax, shellac wax, castorwax, rice wax, modified natural wax, partial synthetic wax, polyethylenewax that is based on polyethylene, chemically modified wax, esterifiedchemically modified wax, saponified chemically modified wax, substitutedamide waxes, polymerized α-olefins waxes, synthetic wax, or combinationsthereof. Other suitable types of non-surfactant additives based on waxchemistry will be apparent to those of skill in the art and are to beconsidered within the scope of the present invention.

Numerous approaches have been used to incorporate sulfur into asphaltcompositions in the past. In such prior attempts, sulfur has been addedin a range of between about 5 wt. % to about 70 wt. % sulfur intoasphalt and non-asphalt based binders to perform in asphalt pavementapplications. None of the previous techniques used the combination ofadditives/modifiers and developed a performance graded binderspecifically for warm mix asphalt applications. More specifically to beable to compact asphalt from about 30° F. to about 70° F. belowconventional asphalt mixtures and obtain equal or better performance ata reduced total raw material cost.

The mixing of sulfur under high shear in loadings from 20-50 wt. %produced a binder with improved low temperature properties and reducedhigh temperature viscosities. The combination of this binder containingpolymers having saturated backbone macromolecules with macromolecularmodifications (co-polymer, ter-polymer, graft-block co or ter-polymer(random, alternating, block, graft-block that can contain reactivefunctionality)), non-surfactant additives based on wax chemistry, suchas Sasobit® wax and/or PPA produced a compound with macromolecularmodified asphalt properties that can be used as a warm mix binder at areduced overall raw material cost. In an aspect, the non-surfactantadditives based on wax chemistry can include special fine crystallinelong chain aliphatic hydrocarbons. The compositions and methods of thepresent invention can lend itself to using modified asphalts in warm mixapplications, where it is currently limited by the high viscosity ofmodified binders. Besides the advantages related to the physicalproperties of the compounds of the present invention, using these typesof binders in warm mix applications further reduces the possibleemissions of H₂S.

Historically, sulfur has had limited use in asphalt due to thegeneration of hydrogen sulfide at temperatures where asphalt is used.Sulfur has been used in very low percentages of 0.1 wt. %-5.0% wt. % bythe weight of polymer as a crosslinking agent for use with polymers, buthas limited use due to the temperatures required for these mixes. Thecurrent invention allows for the use of sulfur with specificmacromolecules at reduced temperatures. The addition of sulfur has beenshown when mixed under high shear to dramatically reduce the rotationalviscosity and other high temperature related properties. By combiningsulfur with other additives, as described herein, the enhanced synergiesof the components are obtained. Sulfur, when mixed with Elvaloy®polymers, has produced a polymer with improved high temperatureproperties. When this combination is further reacted with polyphosphoricacid and sulfur, the performance is enhanced. The polyphosphoric acidand sulfur react at the lower temperatures (250-275° F.) and provide anenhanced binder. These binders can also perform better than conventionalpolymer modified binders, providing a more workable warm mix with bettercompaction.

Most prior attempts at using sulfur modified asphalt compositionsdescribe polymerizing sulfur with hydrocarbons of specific functionalityto produce a polysulfidic structure. These types of materials do notdisplay the same rheological response of asphalt and tend to have poorlow temperature properties and poor aging properties, particularly whencompared to compositions made in accordance with embodiments of thepresent invention.

When asphalt used in combination with additives such as Sasobit® wax,low temperature properties have been negatively impacted significantlylimiting the applicability at lower temperatures. The negative impact ofthe Sasobit® wax at low temperatures is improved by the incorporation ofsulfur resulting in an improved low and high temperature property warmmix sulfur modified asphalt allowing the applicability and utilizationat lower temperature application.

The addition of sulfur with PPA produces a binder with lower hightemperature viscosities, and improved overall performance based on thereaction of the sulfur and PPA at lower temperatures and warm mixprocessability.

Embodiments of the current invention allow for the utilization of sulfurwith specific saturated backbone macromolecules with macromolecularmodifications (co-polymer, ter-polymer, graft-block co or ter-polymer(random, alternating, block, graft-block that can contain reactivefunctionality)) at reduced temperatures. The addition of sulfur has beenshown when mixed under high shear to dramatically reduce the rotationalviscosity and other high temperature related properties. By combiningsulfur with other additives, you can get the synergies of the variouscomponents. Sulfur, when mixed with Elvaloy® polymer, has produced apolymer with improved high temperature properties. When this combinationis further reacted with PPA and sulfur, the performance is enhanced. Thepolyphosphoric acid and sulfur react at the lower temperatures (250-275°F.) and provide an enhanced binder. These binders can also performbetter than conventional polymer modified binders, providing a moreworkable warm mix with better compaction.

Use of the compositions of the present invention have resulted in thedevelopment of lower cost warm mix asphalt binder compositions usingbetween 20-50 wt. % sulfur loading. The sulfur modified asphalt bindercompositions of the present invention can be handled and treated as aperformance grade binder. For example, the combination of 64-22 asphalt,sulfur, PPA, saturated backbone macromolecules with macromolecularmodifications (co-polymer, ter-polymer, graft-block co or ter-polymer(random, alternating, block, graft-block that can contain reactivefunctionality)), and Sasobit® wax produces a PG 76-22 asphalt binderthat can be used for warm mix applications.

The compositions and methods of the present invention allow for highloading of sulfur in asphalt binders that can be used in warm mixasphalt applications in existing hot mix asphalt plants. Thecompositions and methods of the present invention also provide forreduced exposure to hydrogen sulfide generation by use as a warm mixasphalt binder.

Embodiments of the present invention that include a sulfur modifiedcompound can be used in road construction application. The technologyused in embodiments of the present invention include several differentattributes that provide enhanced performance while using sulfur modifiedasphalt.

In an aspect, sulfur is incorporated into compounds in the weightpercents ranging from about 20 wt. % to about 50 wt. % in conjunctionwith PPA and any saturated polymer having backbone macromolecules(ethylene, propylene, butylenes, etc.) with macromolecular modifications(co-polymer, ter-polymer, graft-block co or ter-polymer (random,alternating, block, graft-block that can contain reactivefunctionality)). The polymer can be present in a range of about 0 toabout 5 wt. %. The compositions of the present invention incorporate theuse of PPA with a high loading of sulfur. Furthermore, the compositionsare capable of being a performance grade binder that have high sulfurloading polymer modified asphalt with low rotational viscosity.

Several advantages exist when using the compositions and methods of thepresent invention. As a first advantage, compositions are produced usinga macromolecular modified highly loaded sulfur asphalt binder at a lowertotal material cost with equal of better performance when compared withtraditional asphalt compositions.

As an advantage of the present invention, a highly sulfur loadedmodified asphalt can be made that can be performance graded and utilizedas a warm mix asphalt binder. Additionally, a significant improvement ofthe low temperature properties of the binder and high temperatureprocessability with sulfur used in embodiments of the present inventionwas observed.

When warm mix additives are used in asphalt compositions, the warm mixadditives tend to increase the cost per ton of asphalt being producedfrom $1.25-$3.00/ton. The use of 20-50 wt. % sulfur in the asphaltdramatically reduces the total raw material cost, while still providingequal/better performance.

EXAMPLES Example 1

In Experiment A, base PG 64-22 asphalt modified with 1.5 wt. % Elvaloy®polymer and 0.5 wt. % 115% PPA and was compared to the same blend withthe addition of 20 wt. % sulfur and 4.0 wt. % Sasobit® wax, inaccordance with embodiments of the present invention. The addition ofsulfur into this compound provided several advantageous attributes thatcould not be obtained economically by other methods.

The base PG 64-22 with 0.5 wt. % PPA and 1.5 wt. % Elvaloy® polymerproduced a binder with a PG 70-22 with an effective temperature range of74.0-27.5, as shown in Table 2. This binder also displayed a highRotational Viscosity of 1.563 Pa·sec. When this compound was made byblending 20 wt. % sulfur under high shear into the blend and then beingsubsequently modified, in accordance with embodiments of the presentinvention, enhanced performance was observed both at the processingtemperature and at low temperatures. The sulfur modified binderdisplayed a 62% reduction in rotational viscosity at 135° C., whileimproving the effective temperature range to 73.2-30.3 for a PG 70-28binder, as shown in Table 3.

The addition of 4.0 wt. % Sasobit® wax to the binder, in accordance withembodiments of the present invention, dropped the rotational viscosityto 0.328 Pa-sec, as shown in Table 4. The rotational viscosity displayeda 45% decrease at 135° C. with the addition of Sasobit® wax, but alsoimpacted the effective temperature range. The effective temperaturerange was 84.7-16.2, which was over a two grade reduction on the lowtemperature side, while only providing a grade and half at the high end.The effective temperature range of this binder makes it ideal for use inextreme hot climate conditions.

The resulting properties are significant because a binder having acomparable performance grading typically requires the use of a highpercentage of polymer >4 wt. % and the use of a very soft base asphaltto maintain the low temperature properties. In this Example 1, there isa synergistic reaction between the PPA and sulfur that provides theadditional improvement at the low end, while reducing the hightemperature rotational viscosity. The compositions and methods of thepresent invention can lend itself to using modified asphalts in warm mixapplications, where such applications are currently limited by the highviscosity of modified binders. Furthermore, using these types of bindersin warm mix applications further reduces the possible emissions of H₂S.

Typically, the addition of only sulfur can produce embrittlement duringaging. The sulfur modified compound of the present invention showedbetter properties after PAV aging (lower G*·Sin δ Delta) for a giventemperature. The sulfur compound of the present invention displayed avalue of 5,390 kPa at 16° C. versus the non-sulfur modified binder thatdisplayed a value of 6,680 kPa at 16° C., which is statistically higher.The improvement is at least partially related to the synergistic effectbetween PPA and the sulfur.

TABLE 2 PG Determination for Binder A - Base, (PG 64-22, w/1.5% ElvaloyRET & 0.5% 115% PPA) AASHTO TEST PROPERTY METHOD SPECIFICATIONS RESULTSORIGINAL BINDER Specific Gravity 15.6° C.   T 228 Report 1.034 SofteningPoint, ° C. (° F.) ASTM D 36 Report 63 (145) Penetration (100 grams, 5sec.), 25° C. T 49 Report 71 dmm Viscosity, Pa · s 135° C.  T 316 3.0max. 1.563 165° C.  Report 0.320 Separation, R&B Difference, 48 hrs.,163° C.  ° C. (° F.) Top, ⅓, Softening Point, ° C. (° F.) ASTM D Report60.6 (141.0) Bottom, ⅓, Softening Point, ° C. (° F.) 5892 60.3 (140.5)Difference, ° C. (° F.) 2 (4) max. 0.3 (0.5)  Dynamic Shear (G*/sin δ,10 rad./sec.), T 315 1.0 min. G* δ G*/sin δ kPa 64° C. 3.620 64.6 4.01082° C. 0.760 69.3 0.813 AFTER RTFOT @ 135° C. Mass Change, % (Mass Lossis reported as T 240 1.0 max. −0.023 Negative) Dynamic Shear (G*/sin δ,10 rad./sec.), T 315 2.2 min. G* δ G*/sin δ kPa 70° C. 2.740 62.4 3.09076° C. 1.650 63.5 1.850 MSCR 0.1 kPa % Rec. 64° C. TP 70-08 Report 65.3Jnr 0.30 3.2 kPa % Rec. 62.1 Jnr 0.31 PRESSURE AGING RESIDUE (100° C., R28 300 psi, 20 hr.) Dynamic Shear (G* · sin δ, 10 rad./sec.), T 315Report G* δ G* · sin δ kPa 16° C. 5,000 max. 9,660 43.8 6,680 28° C.1,560 53.8 1,260 Creep Stiffness, MPa (60 sec.) −12° C.   T 313 300 max.136 Stiffness m Value 0.300 min. 0.373 Stiffness, MPa (60 sec.) −18°C.   300 max. 322 m Value 0.300 min. 0.302 ‘True’ Performance Grade74.0-27.5 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG: PG 70-22

TABLE 3 PG Determination for Binder A - Sulfur, (PG 64-22, w/1.5%Elvaloy RET & 0.5% PPA & 20 Wt. % Sulfur) AASHTO TEST PROPERTY METHODSPECIFICATIONS RESULTS ORIGINAL BINDER H₂S Emissions, ppm DetectorReport 5 ppm Before, 40 ppm Tubes After Specific Gravity 15.6° C.   T228 Report 1.118 Softening Point, ° C. (° F.) ASTM D 36 Report 60 (140)Penetration (100 grams, 5 sec.), 25° C. T 49 Report 82 dmm Viscosity, Pa· s 135° C.  T 316  3.0 max. 0.593 Dynamic Shear (G*/sin δ, 10rad./sec.), T 315  1.0 min. G* δ G*/sin δ kPa 70° C. 1.230 64.7 1.36076° C. 0.710 67.5 0.769 AFTER RTFOT @ 135° C. Mass Change, % (Mass Lossis reported T 240  1.0 max. −0.925 as Negative) Dynamic Shear (G*/sin δ,10 rad./sec.), T 315  2.2 min. G* δ G*/sin δ kPa 70° C. 3.820 63.6 4.26076° C. 2.210 65.9 2.420 82° C. 1.210 69.1 1.300 MSCR 0.1 kPa % Rec. 64°C. TP 70-08 Report 43.9 Jnr 0.76 3.2 kPa % Rec. 20.3 Jnr 1.24 PRESSUREAGING RESIDUE (100° C., R 28 300 psi, 20 hr.) Dynamic Shear (G* · sin δ,10 rad./sec.), T 315 Report G* δ G* · sin δ kPa 16° C. 5,000 max. 8,10041.7 5,390 25° C. 2,100 48.7 1,580 Creep Stiffness, MPa −18° C.   T 313  300 max. 207 Stiffness (60 sec.) m Value 0.300 min. 0.325 Stiffness,MPa −24° C.     300 max. 414 (60 sec.) m Value 0.300 min. 0.263 ‘True’Performance Grade 73.2-30.3 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG:70-28

TABLE 4 PG Determination for Binder A - Sasobit ® wax, (PG 64-22, w/1.5%Elvaloy RET & 0.5% PPA & 20 Wt. % Sulfur & 4.0 wt. % Sasobit) AASHTOTEST PROPERTY METHOD SPECIFICATIONS RESULTS ORIGINAL BINDER SpecificGravity 15.6° C.   T 228 Report 1.129 Viscosity, Pa · s 135° C.  T 316 3.0 max. 0.328 Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315  1.0 min.G* δ G*/sin δ kPa 82° C. 2.170 63.9 2.420 88° C. 0.801 68.2 0.863 AFTERRTFOT Mass Change, % (Mass Loss is reported as T 240  1.0 max. −0.729Negative) Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315  2.2 min. G* δG*/sin δ kPa 82° C. 2.470 60.1 2.850 88° C. 1.440 64.1 1.600 PRESSUREAGING RESIDUE (100° C., R 28 300 psi, 20 hr.) Dynamic Shear (G* · sin δ,10 rad./sec.), T 315 Report G* δ G* · sin δ kPa 25° C. 5,000 max. 5,94035.2 3,430 22° C. 8,330 33.8 4,640 Creep Stiffness, MPa (60 sec.) −6° C.T 313   300 max. 83 Stiffness m Value 0.300 min. 0.301 Stiffness, MPa(60 sec.) −12° C.     300 max. 152 m Value 0.300 min. 0.276 ‘True’Performance Grade 84.7-16.2 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG:PG 82-16

Example 2

A sulfur modified compound has been developed in accordance withembodiments of the present invention that can be used in the roadconstruction. The technology of the present invention results in severaldifferent unique attributes that provide unexpected performanceproperties while using sulfur modified asphalt. The basis for thetechnology is the incorporation of elemental sulfur into compounds inthe weight percents from 20-50 wt. % in conjunction with polyphosphoricacid.

In Experiment B, a base PG 64-28 asphalt modified with 0.5 wt. % 115%PPA, as shown in Table 5, was compared to the same blend with theaddition of 20 wt. % (Table 6) sulfur and 3.5 wt. % Sasobit® wax, asshown in Table 7. The addition of sulfur into this compound providedseveral unique attributes that could not be obtain economically by othermethods.

The base PG 64-28 with 0.5 wt. % PPA produced a binder with a PG 64-28rating with an effective temperature range of 69.2-31.4, as shown inTable 5. This binder also displayed a Rotational Viscosity of 0.745Pa-sec. When this compound was made by blending 20 wt. % sulfur underhigh shear into the blend in accordance with embodiments of the presentinvention and then subsequently modifying enhanced performance wasobserved both at the processing temperature and low temperatures. Thesulfur modified binder displayed a 64% reduction in rotational viscosityat 135° C., while improving the effective temperature range to 65.9-34.3for a PG 64-34 binder, as shown in Table 6.

When 3.5 wt. % Sasobit® wax was subsequently added to PG 64-28, 0.5 wt.% 115% PPA and 20 wt. % Sulfur further benefits were observed, as shownin Table 7. The addition of Sasobit® wax decreased the rotationalviscosity at 135° C. to 0.226 Pa-sec and also increased the hightemperature grade to 79.1-27.3. The combination of sulfur and Sasobit®wax produced a binder with an effective temperature range of 106.4degrees. There was a change in the low temperature grade from −34.3 to−27.3, but still produced excellent low temperature properties. Therewas an effective 6 degree improvement in the grade with a 17% decreasein rotational viscosity. The results obtained using this compositionmake this composition an ideal binder for use in warm mix asphaltapplications.

The resulting properties are significant because a binder having acomparable performance grading typically requires the use of a highpercentage of polymer >4 wt. % and the use of a very soft base asphaltto maintain the low temperature properties. In this Example, there is asynergistic reaction between the PPA and sulfur that provides theadditional improvement at the low end, while reducing the hightemperature rotational viscosity. The compositions and methods of thepresent invention can lend itself to using modified asphalts in warm mixapplications, where it is currently limited by the high viscosity ofmodified binders. Furthermore, using these types of binders in warm mixapplications further reduces the possible emissions of H₂S.

TABLE 5 PG Determination for Binder B - Base, (PG 64-28, w/0.5% PPA)AASHTO TEST PROPERTY METHOD SPECIFICATIONS RESULTS ORIGINAL BINDER FlashPoint, ° C. (° F.) T 48   230 min. 273 (524) Specific Gravity 15.6° C.  T 228 Report 1.034 Softening Point, ° C. (° F.) ASTM D 36 Report  57(135) Penetration (100 grams, 5 sec.), 25° C. T 49 Report 67 dmmViscosity, Pa · s 135° C.  T 316  3.0 max. 0.745 165° C.  Report 0.179Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315  1.0 min. G* δ G*/sin δkPa 64° C. 2.180 78.2 2.230 70° C. 1.120 80.7 1.130 AFTER RTFOT @ 135°C. Mass Change, % (Mass Loss is reported as T 240  1.0 max. −0.158Negative) Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315  2.2 min. G* δG*/sin δ kPa 64° C. 3.990 74.0 4.150 70° C. 2.060 76.6 2.120 MSCR 0.1kPa % Rec. 64° C. TP 70-08 Report 27.5 Jnr 1.00 3.2 kPa % Rec. 7.05 Jnr1.49 PRESSURE AGING RESIDUE (100° C., R 28 300 psi, 20 hr.) DynamicShear (G* · sin δ, 10 rad./sec.), T 315 Report G* δ G* · sin δ kPa 16°C. 5,000 max. 8,270 42.7 5,610 19° C. 5,410 44.8 3,810 22° C. 3,460 46.82,520 Creep Stiffness, MPa (60 sec.) −18° C.   T 313   300 max. 203Stiffness m Value 0.300 min. 0.364 Stiffness, MPa (60 sec.) −24° C.    300 max. 405 m Value 0.300 min. 0.281 ‘True’ Performance Grade69.7-31.4 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG: 64-28

TABLE 6 PG Determination for Binder B - Sulfur, (PG 64-28, w/ 0.5% 115%PPA & 20 Wt. % Sulfur) AASHTO TEST PROPERTY METHOD SPECIFICATIONSRESULTS ORIGINAL BINDER H2S Emissions, Detector Report 0 ppm Before, 80ppm ppm Tubes After Specific Gravity 15.6° C.   T 228 Report 1.135Softening Point, ° C. (° F.) ASTM D 36 Report 50 (122) Penetration (100grams, 5 sec.), 25° C. T 49 Report 126 dmm Viscosity, Pa · s 135° C.  T316  3.0 max. 0.272 Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315  1.0min. G* δ G*/sin δ kPa 64° C. 1.320 75.9 1.360 70° C. 0.663 79.5 0.675AFTER RTFOT @ 135° C. Mass Change, % (Mass Loss is reported T 240  1.0max. −0.888 as Negative) Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315 2.2 min. G* δ G*/sin δ kPa 64° C. 2.520 73.6 2.620 70° C. 1.470 77.41.510 MSCR 0.1 kPa % 64° C. TP 70-08 Report 16.3 Rec. Jnr 3.29 3.2 kPa %1.9 Rec. Jnr 5.86 PRESSURE AGING RESIDUE R 28 (100° C., 300 psi, 20 hr.)Dynamic Shear (G* · sin δ, 10 rad./sec.), T 315 Report G* δ G* · sin δkPa 16° C. 5,000 max. 7,610 42.0 5,100 19° C. 4,820 44.3 3,370 CreepStiffness, MPa −18° C.   T 313   300 max. 141 Stiffness (60 sec.) mValue 0.300 min. 0.360 Stiffness, MPa −24° C.     300 max. 289 (60 sec.)m Value 0.300 min. 0.319 ‘True’ Performance Grade 65.9-34.3 AASHTO M 320SUPERPAVE ™ Binder Grade, PG: 64-34

TABLE 7 PG Determination for Binder B - Sasobit ® wax (PG 64-28, w/ 0.5%115% PPA & 20 Wt. % Sulfur & 3.5 wt. % Sasobit) AASHTO TEST PROPERTYMETHOD SPECIFICATIONS RESULTSP ORIGINAL BINDER Specific Gravity 15.6°C.   T 228 Report 1.139 Viscosity, Pa · s 135° C.  T 316  3.0 max. 0.226Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315  1.0 min. G* δ G*/sin δkPa 76° C. 1.630 77.5 1.670 82° C. 0.614 81.1 0.622 AFTER RTFOT (135°C.) Mass Change, % (Mass Loss is reported as T 240  1.0 max. −0.811Negative) Dynamic Shear (G*/sin δ, 10 rad./sec.), T 315  2.2 min. G* δG*/sin δ kPa 76° C. 3.130 66.8 3.410 82° C. 1.770 69.0 1.900 PRESSUREAGING RESIDUE (100° C., R 28 300 psi, 20 hr.) Dynamic Shear (G* · sin δ,10 rad./sec.), T 315 Report G* δ G* · sin δ kPa 19° C. 5,000 max. 7,97038.3 4,940 16° C. 11,500 36.8 6,870 Creep Stiffness, MPa (60 sec.) −12°C.   T 313   300 max. 102 Stiffness m Value 0.300 min. 0.323 Stiffness,MPa (60 sec.) −18° C.     300 max. 198 m Value 0.300 min. 0.297 ‘True’Performance Grade 79.1-27.3 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG:PG 76-22

Example 3

A sulfur modified compound has been developed in accordance withembodiments of the present invention that can be used in the roadconstruction. The technology consists of several different uniqueattributes that provide unique performance properties while using sulfurmodified asphalt. The basis for the technology is the incorporation ofelemental sulfur into compounds in the weight percents from 20-50 wt. %in conjunction with polyphosphoric acid and saturated polyolefinelastomers. In Experiment C, a base PG 64-28 asphalt modified with 0.5wt. % 115% PPA, as shown in Table 8, was compared to the same blend withthe addition of 50 wt. % sulfur, as shown in Table 9, and 3.5 wt. %Sasobit® wax, in accordance with embodiments of the present invention.The addition of sulfur into this compound provided several uniqueattributes that could not be obtain economically by other methods. Thebase PG 64-28 with 0.5 wt. % PPA produced a binder with a PG 64-28 withan effective temperature range of 69.2-31.4, as shown in Table 7. Thisbinder also displayed a Rotational Viscosity of 0.745 Pa-sec. Thisbinder also displayed a high Rotational Viscosity of 1.593 Pa-sec. Whenthis compound was made by blending 50 wt. % sulfur under high shear intothe blend and then subsequently modifying, enhanced performance wasobserved with a 53% reduction in rotational viscosity at 135° C., whileimproving the effective temperature range to 69.1-30.0 for a PG 64-28binder, as shown in Table 8. The addition of 3.5 wt. % Sasobit® wax didnot show any substantial further decrease in the rotational viscosity.

The resulting properties are significant because a binder having acomparable performance grading typically requires the use of a highpercentage of polymer >4 wt. % and the use of a very soft base asphaltto maintain the low temperature properties. In this Example, there is asynergistic reaction between the PPA and sulfur that provides theadditional improvement at the low end, while reducing the hightemperature rotational viscosity. The compositions and methods of thepresent invention can lend itself to using modified asphalts in warm mixapplications, where it is currently limited by the high viscosity ofmodified binders. Additionally, using these types of binders in warm mixapplications further reduces the possible emissions of H₂S.

TABLE 8 PG Determination for Binder C- Base (PG 64-28, w/ 0.5% 115% PPA)AASHTO TEST PROPERTY METHOD SPECIFICATIONS RESULTS ORIGINAL BINDER FlashPoint, ° C. (° F.) T 48 230 min. 271 (520) Specific Gravity 15.6° C.   T228 Report 1.035 Softening Point, ° C. (° F.) ASTM D 36 Report  50 (122)Penetration (100 grams, 5 sec.), 25° C. T 49 Report 70 dmm Viscosity, Pa· s 135° C.  T 316 3.0 max. 0.690 165° C.  Report 0.197 Separation, R&BDifference, 163° C.  48 hrs., ° C. (° F.) Top, ⅓, Softening Point, ° C.(° F.) ASTM D Report  52.2 (126.0) Bottom, ⅓, Softening Point, ° C. (°F.) 5892  51.7 (125.0) Difference, ° C. (° F.) 2 (4) max. 0.5 (1.0)Dynamic Shear (G*/sin δ, T 315 1.0 min. G* δ G*/sin δ 10 rad./sec.), kPa64° C. 1.710 81.5 1.730 70° C. 0.880 83.6 0.885 AFTER RTFOT @ 135° C.Mass Change, % (Mass Loss is reported T 240 1.0 max. −0.103 as Negative)Dynamic Shear (G*/sin δ, T 315 2.2 min. G* δ G*/sin δ 10 rad./sec.), kPa64° C. 2.740 77.6 2.800 70° C. 1.410 79.7 1.430 MSCR 0.1 kPa % 64° C. TP70-08 Report 24.3 Rec. Jnr 1.80 3.2 kPa % 7.7 Rec. Jnr 2.69 PRESSUREAGING RESIDUE R 28 (100° C., 300 psi, 20 hr.) Dynamic Shear (G* · sin δ,T 315 Report G* δ G* · sin δ 10 rad./sec.), kPa 16° C. 5,000 max. 9,05043.3 6,200 19° C. 5,840 45.6 4,170 Creep Stiffness, MPa −18° C.   T 313300 max. 246 Stiffness (60 sec.) m Value 0.300 min. 0.322 Stiffness, MPa−24° C.   300 max. 465 (60 sec.) m Value 0.300 min. 0.274 ‘True’Performance Grade 66.2-29.9 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG:PG 64-28

TABLE 9 PG Determination for Binder C- Sulfur (PG 64-28, w/ 0.5% 115%PPA & 50 wt. % Sulfur) AASHTO TEST PROPERTY METHOD SPECIFICATIONSRESULTS ORIGINAL BINDER H₂S Emissions, ppm Detector Report After 35 ppmTubes Specific Gravity 15.6° C.   T 228 Report 1.203 Softening Point, °C. (° F.) ASTM D 36 Report 68 (154) Penetration (100 grams, 5 sec.), 25°C. T 49 Report 33 dmm Viscosity, Pa · s 135° C.  T 316 3.0 max. 0.350Dynamic Shear (G*/sin δ, T 315 1.0 min. G* δ G*/sin δ 10 rad./sec.), kPa64° C. 1.680 73.1 1.760 70° C. 0.878 76.0 0.905 AFTER RTFOT @ 135° C.Mass Change, % (Mass Loss is reported T 240 1.0 max. −0.822 as Negative)Dynamic Shear (G*/sin δ, T 315 2.2 min. G* δ G*/sin δ 10 rad./sec.), kPa76° C. 3.300 76 3.400 82° C. 1.670 79.1 1.700 MSCR 0.1 kPa % 64° C. TP70-08 Report 53.2 Rec. Jnr 0.03 3.2 kPa % 16.4 Rec. Jnr 0.11 PRESSUREAGING RESIDUE R 28 (100° C., 300 psi, 20 hr.) Dynamic Shear (G* · sin δ,T 315 Report G* δ G* · sin δ 10 rad./sec.), kPa 19° C. 5,000 max. 11,50036.4 6,830 22° C. 8,120 37.8 4,980 Creep Stiffness, MPa −18° C.   T 313300 max. 86 Stiffness (60 sec.) m Value 0.300 min. 0.321 Stiffness, MPa−24° C.   300 max. 266 (60 sec.) m Value 0.300 min. 0.262 ‘True’Performance Grade 69.1-30.0 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG:64-28

Example 4

A sulfur modified compound has been developed in accordance withembodiments of the present invention that can be used in the roadconstruction. The technology of the present invention results in severaldifferent unique attributes that provide unique performance propertieswhile using sulfur modified asphalt. The basis for the technology is theincorporation of elemental sulfur into compounds in the weight percentsfrom 20-50 wt. % in conjunction with polyphosphoric acid and saturatedpolyolefin elastomers.

In Experiment D, base PG 64-22 asphalt modified with 1.5 wt. % Elvaloy®polymer (see Table 10) was compared to the same blend with the additionof 20 wt. % sulfur (see Table 11) and 3.5 wt. % Sasobit® wax inaccordance with embodiments of the present invention (see Table 12). Theaddition of sulfur into this compound provided several unique attributesthat could not be obtain economically by other methods. The base PG64-22 with 1.5 wt. % Elvaloy® polymer produced a binder with a PG 64-28with an effective temperature range of 64.2-27.7 (see Table 10). Thisbinder also displayed a Rotational Viscosity of 0.590 Pa-sec. When thiscompound was made by blending 20 wt. % sulfur under high shear into theblend and then subsequently modifying, enhanced performance was observedwith a large reduction in rotational viscosity at 135 C, while improvingthe effective temperature range to 69.4-28.2 for a PG 64-28 binder (seeTable 11). The addition of 3.5 wt. % Sasobit® wax in accordance withembodiments of the present invention did show a further decrease in therotational viscosity (see Table 12). The addition of 3.5 wt. % Sasobit®wax further dropped the rotational viscosity to 0.228 Pa-sec. Theeffective binder grade was 79.8-22.2. This binder showed an increase inthe high temperature side, while further lowering the rotationalviscosity making it an ideal binder for warm mix applications.

The resulting properties are significant because a binder having acomparable performance grading typically requires the use of a highpercentage of polymer >4 wt. % and the use of a very soft base asphaltto maintain the low temperature properties. In this case, there is asynergistic reaction between the PPA and sulfur that provides theadditional improvement at the low end, while reducing the hightemperature rotational viscosity. The compositions and methods of thepresent invention can result in the modified asphalt compositions beingused in warm mix applications, where it is currently limited by the highviscosity of modified binders. Furthermore, using these types of bindersin warm mix applications further reduces the possible emissions of H₂S.

TABLE 10 PG Determination of Base Binder D (PG 64-22, 1.5 wt. % Elvaloy)AASHTO TEST PROPERTY METHOD SPECIFICATIONS RESULTS ORIGINAL BINDER FlashPoint, ° C. (° F.) T 48 230 min. 318 (604) Specific Gravity 15.6° C.   T228 Report 1.032 Softening Point, ° C. (° F.) ASTM D 36 Report  51 (124)Penetration (100 grams, 5 sec.), 25° C. T 49 Report 85 dmm Viscosity, Pa· s 135° C.  T 316 3.0 max. 0.590 165° C.  Report 0.171 Separation, R&BDifference, 163° C.  48 hrs., ° C. (° F.) Top, ⅓, Softening Point, ° C.(° F.) ASTM D Report  52.4 (126.25) Bottom, ⅓, Softening Point, ° C. (°F.) 5892  52.4 (126.25) Difference, ° C. (° F.) 2 (4) max. 0.0 (0.0)Dynamic Shear (G*/sin δ, T 315 1.0 min. G* δ G*/sin δ 10 rad./sec.), kPa64° C. 1.420 85.8 1.420 70° C. 0.711 87.1 0.711 AFTER RTFOT @ 135° C.Mass Change, % (Mass Loss is reported as T 240 1.0 max. −0.006 Negative)Dynamic Shear (G*/sin δ, T 315 2.2 min. G* δ G*/sin δ 10 rad./sec.), kPa64° C. 2.220 83.6 2.240 70° C. 1.090 85.1 1.100 MSCR 0.1 kPa % Rec. 64°C. TP 70-08 Report 11.5 Jnr 3.19 3.2 kPa % Rec. 1.9 Jnr 4.00 PRESSUREAGING RESIDUE (100° C., R 28 300 psi, 20 hr.) Dynamic Shear (G* · sin δ,T 315 Report G* δ G* · sin δ 10 rad./sec.), kPa 19° C. 5,000 max. 7,16046.2 5,170 25° C. 2,780 52.5 2,180 Creep Stiffness, MPa −12° C.   T 313300 max. 169 Stiffness (60 sec.) m Value 0.300 min. 0.356 Stiffness, MPa−18° C.   300 max. 309 (60 sec.) m Value 0.300 min. 0.299 ‘True’Performance Grade 64.2-27.7 AASHTO M 320 SUPERPAVE ™ Binder Grade, PG:PG 64-22

TABLE 11 PG Determination of Base Binder D - Sulfur (PG 64-22, 1.5 wt. %Elvaloy & 20 wt. % Sulfur) AASHTO TEST PROPERTY METHOD SPECIFICATIONSRESULTS ORIGINAL BINDER H2S Emissions, ppm Detector Report 0.0 ppmBefore, 21 ppm Tubes After Specific Gravity 15.6° C.   T 228 Report1.073 Softening Point, ° C. (° F.) ASTM D 36 Report 65 (149) Penetration(100 grams, 25° C. T 49 Report 62 5 sec.), dmm Viscosity, Pa · s 135°C.  T 316  3.0 max. 0.295 Dynamic Shear (G*/sin δ, T 315  1.0 min. G* δG*/sin δ 10 rad./sec.), kPa 64° C. 2.210 84.4 2.220 70° C. 1.120 85.71.120 76° C. 0.562 86.7 0.563 AFTER RTFOT @ 135° C. Mass Change, % (MassLoss T 240  1.0 max. −0.743 is reported as Negative) Dynamic Shear(G*/sin δ, T 315  2.2 min. G* δ G*/sin δ 10 rad./sec.), kPa 64° C. 3.68073.8 3.830 70° C. 1.970 73.1 2.060 MSCR 0.1 kPa % 64° C. TP 70-08 Report10.7 Rec. Jnr 6.84 3.2 kPa % 1.30 Rec. Jnr 9.85 PRESSURE AGING RESIDUE R28 (100° C., 300 psi, 20 hr.) Dynamic Shear (G* · sin δ, T 315 Report G*δ G* · sin δ 10 rad./sec.), kPa 16° C. 5,000 max. 10,300 39.2 6,540 19°C. 6,780 41.5 4,500 22° C. 4,420 43.8 3,060 Creep Stiffness, MPa −12°C.   T 313   300 max. 106 Stiffness (60 sec.) m Value 0.300 min. 0.356Stiffness, MPa −18° C.     300 max. 220 (60 sec.) m Value 0.300 min.0.303 Stiffness, MPa −24° C.     300 max. 468 (60 sec.) m Value 0.300min. 0.234 ‘True’ Performance Grade 69.4-28.2 AASHTO M 320 SUPERPAVE ™Binder Grade, PG: PG 64-28

TABLE 12 PG Determination of Base Binder D - Sasobit ® wax (PG 64-22,1.5 wt. % Elvaloy & 20 wt. % Sulfur, 3.5 wt % Sasobit) AASHTO TESTPROPERTY METHOD SPECIFICATIONS RESULTS ORIGINAL BINDER Specific Gravity15.6° C.   T 228 Report 1.131 Viscosity, Pa · s 135° C.  T 316  3.0 max.0.228 Dynamic Shear (G*/sin δ, T 315  1.0 min. G* δ G*/sin δ 10rad./sec.), kPa 82° C. 0.891 57.7 1.050 88° C. 0.450 58.4 0.528 AFTERRTFOT (135° C.) Mass Change, % (Mass Loss is reported as T 240  1.0 max.−0.690 Negative) Dynamic Shear (G*/sin δ, T 315  2.2 min. G* δ G*/sin δ10 rad./sec.), kPa 76° C. 2.730 54.8 3.350 82° C. 1.410 55.2 1.710PRESSURE AGING RESIDUE (100° C., R 28 300 psi, 20 hr.) Dynamic Shear (G*· sin δ, T 315 Report G* δ G* · sin δ 10 rad./sec.), kPa 22° C. 5,000max. 7,820 4,890 54.8 19° C. 11,300 36.6 6,750 Creep Stiffness, MPa (60sec.) −12° C.   T 313   300 max. 146 Stiffness m Value 0.300 min. 0.301Stiffness, MPa (60 sec.) −18° C.     300 max. 289 m Value 0.300 min.0.265 ‘True’ Performance Grade 79.8-22.2 AASHTO M 320 SUPERPAVE ™ BinderGrade, PG: PG 76-22

Example 5

A sulfur modified compound has been developed in accordance withembodiments of the present invention that can be used in roadconstruction. More specifically, the binder described in Example 4 canbe used in a warm mix application. Existing warm mix additives can bedefined by a wide range of technologies. Sulfur provides a means to usea waste stream material from the sour gas treatment process and refiningprocess to create a warm mix additive.

The PG 64-22 binder with 20 wt. % sulfur, 1.5 wt. % Elvaloy® polymer and3.5 wt. % Sasobit® wax (as shown in Table 11) was used in a warm mixasphalt mixture. The use of this binder reduced the mixing andcompaction temperature versus a conventional mix by 50° F.+. Thisreduction qualifies the material as a warm mix asphalt composition.Furthermore, the composition had a significantly higher performancegrading. Performance tests were subsequently performed on the mix andcompared to the mixture using the PG 64-22 control (as shown in Table10). Several significant findings were observed and are unique withrespect to warm mix asphalt. Several issues have been identified withwarm mix asphalt related to the tenderness of the mix due to reducedoxidative aging of the binder during processing and greater moisturesusceptibility. Results in Table 13 show the Resilient Modulus results.The sulfur modified binder Blend No. 5, which was prepared in accordancewith embodiments of the present invention, displayed a higher ResilientModulus at 40° C. and a lower Resilient Modulus at 5° C. demonstratingthe improved performance properties of the mix with this binder. MostWarm Mix binders tend to have reduced the stiffness at hightemperatures. The Resilient Modulus results indicated that sulfurmodified asphalt mixtures tended to have better low temperaturesproperties, while the mixture containing the Blend No. 5 also displayedhigher stiffness at 40° C.

TABLE 13 Conclusion Summary (Tensile Strength and Resilient Modulus)Test Results Properties Method Control Blend No. 5 Resilient Modulus ksiMPa ksi MPa Resilient  5° C. ASTM D 2,217 15,286 1,733 11,947 Modulus25° C. 4123 527 3,634 520 3,589 40° C. 145 996 165 1,135

The resistance to permanent deformation and moisture susceptibility werefurther emphasized with testing performed on the Hamburg Wheel Tracktest.

Table 14 shows the results of the Blend No. 5 previously discussedversus the control. Blend No. 5 with the 20 wt. % sulfur/1.5 wt. %Elvaloy® polymer/3.5 wt. % Sasobit® wax performed the best and displayed50% greater number of passes to maximum displacement.

TABLE 14 Conclusion Summary (Hamburg Wheel Tracking Test) Test ResultsProperties Method Control Blend No. 5 Compaction Method AASHTO TGytatory Compactor Maximum Deflection, mm 324 20 Number of Passes toFailure, Nf, 11,710 17,970 passes Test Temperature, ° C. 52 Air Voids, %(7.0 +/− 2.0%) 6.8/6.6 7.1/6.8 Stripping Inflection Point (SIP), 7,0009,000 Passes

The observed results are consistent with the large difference in themaximum high temperature grade of the control and Blend No. 5. Thehigher the number of passes to reach maximum displacement indicates amixture less susceptible to permanent deformation and has sufficientbinder stiffness and an adequate aggregate structure. These factors havebeen some of the primary concerns with warm mix asphalt, since thebinder exhibits less oxidative aging compared to conventional binders.Because the samples were submerged in a temperature controlled waterbath during testing, the potential effects of moisture damage could beassessed. When the displacement versus number of passes shows a changein slope, this is termed a Stripping Inflection Point (SIP). The SIPrepresents the number of passes that the deformation is caused bymoisture damage and not rutting alone.

The Stripping Inflection Point for Blend No. 5 versus the controlindicated that it has greater resistance to moisture susceptibilityversus the control. The Stripping Inflection Point for the Blend No. 5was much higher than the control.

Another factor that is considered when evaluating binder compositions isthe stoke count or passes. FIG. 1 shows the Stoke Count (Passes) versusDepth for the Blend No. 2 at 52° C. FIG. 2 shows the Stoke Count(Passes) versus Depth for the Blend No. 5 at 52° C. Typically values of10,000 passes are termed very moisture resistant mixes. The Blend No. 5performed significantly better than the control with respect to theHamburg Wheel Track testing showing the significant improvement in therutting resistance. The Blend No. 5 showed 50% more passes required tomeet maximum deflection as compared to the control. For Blend No. 5, thesulfur modified mixtures actually increased the SIP versus the control.Not only did the warm mix asphalt mixture display good performance, itimproved over the control. It is believed that this unique result hasnot been previously observed in asphalt compositions containing sulfur.

Warm Mix Blend No. 5 also displayed greater resistance to fuels ascompared to the control based on the results in Table 15.

TABLE 15 Resistance of Hot Mix Asphalt to Fuels Test Results PropertiesMethod Control Blend No. 5 Test Temperature PRI Method AmbientTemperature Fuel Used Klean-Strip 1-K Kerosene-Product #E08331 SoakTime, hours 24 Mass Loss after Test, % 3.7 0.0

Several blends were prepared in accordance with embodiments of thepresent invention, as shown in Table 17. Table 16 displays the effectivetemperature range of each of the binder compositions as determined byAASHTO M 320, Table 1. The effective temperature range is the maximumand minimum application temperature in degrees Celsius that the bindercan effectively operate. Blends No. 2 and No. 5 were evaluated for thewarm mix application. These blends showed an increase in the effectivetemperature range of the binder, while decreasing the rotationalviscosity. The other binders either were neutral or decreased theeffective temperature range.

TABLE 16 Conclusion Summary (Warm Mix Binders) Blend No. Viscosity @135° C. True Grade (w/o True Grade (with Temperature (Base Binder)(Pa-s) Rotational Sasobit ® wax) Sasobit ® wax) Range Effective 1 (A21)0.202 62.4-28.7 — — 2 (B21) 0.226 65.9-34.3 79.1-27.3 106.4 3 (B22)0.426 69.1-30.0 — — 4 (B11) 0.180 59.5-33.8 — — 5 (A31) 0.228 69.4-28.279.8-22.2 101.7 6 (A41) 0.328 73.2-30.3 84.7-16.2 100.9 7 (New) 0.260 —83.6-16.2 99.8 8 (F41) 0.232 64.2-25.9 80.7-10.9 91.6

TABLE 17 Warm Mix Binders Elvaloy ® SASOBIT ® Blend Asphalt Sulfur PPApolymer Vamac WAX Binder A (PG 64-22, Gulf Coast) No. 1 77.5 20 0.5 — —2.0 No. 5 75.0 20 — 1.5 — 3.5 No. 6 74.0 20 0.5 1.5 — 4.0 No. 7 74.5 200.5 1.0 — 4.0 No. 8 74.0 20 0.5 — 2.0 3.5 Binder B (PG 64-28, EastCoast) No. 2 76.0 20 0.5 — — 3.5 No. 3 46.0 50 0.5 — — 3.5 No. 4 78.0 20— — — 2.0

A 12.5 mm Superpave Surface Mix Design was selected with the followingaggregate proportions shown in Table 18.

TABLE 18 Aggregate Mix Proportions Superpave Surface Mix Design TrapTrap Trap Trap Rock Rock Rock Combined Actual Design Targets Rock No. 8No. 12.5 No. 10 SD Passing, % Passing, % Control Restricted TestProportion Property Point zone Method 26% 38% 29% 7% 100% ¾″ T 27 100100 100 100 100.0 100.0 ½″ 90-100 82.7 100 100 100 95.5 96.0 ⅜″ 90 max.51.9 96.3 100 100 86.1 86.0 No. 4 11.2 36.2 98.4 98.3 52.1 53.0 No. 828-58 5.0 10.9 69.2 94.9 32.2 33.0 No. 16 4.1 6.7 47.0 85.7 23.2 24.0No. 30 3.7 5.5 34.8 67.3 17.8 18.0 No. 50 3.3 4.8 25.7 30.6 12.3 12.0No. 100 2.7 4.1 18.1 5.1 7.9 8.0 No. 200  2-10 2.0 3.3 12.6 1.4 5.5 5.5

The volumetric properties were based on Optimum Asphalt Content forcontrol PG 64-22. These properties produced the following volumetrics asshown in Table 19.

TABLE 19 Volumetric Properties at Optimum Asphalt Content PropertySpecification Test Method Results Optimum Asphalt Content, % — 5.0 %G_(mm) @ N_(int)* ≦89% 86 % G_(mm) @ N_(desgn)   96% M 323 96 % G_(mm) @N_(max)  <98% (Calculation) 97.5 VMA @ N_(desgn) 14 min 14.1 VFA @N_(desgn) 65-75 72.3

The optimum asphalt content for the control mix was 5.0% % and then theTheoretical Maximum Specific Gravity (Gmm) was determine to be 2.704.This coupled with the Bulk Specific Gravity using an I·N_(design)=100gyrations was 2.594.

Table 20 displays the Warm Mix Asphalt mix design information for thecontrol (PG 64-22), Warm Mix Sulfur Asphalt (WMSA) with Blend No. 2 andWMSA with Blend No. 5. The table displays the volumetrics of thedifferent mixes at an optimum asphalt binder content of 5%, compactedwith N100 Design Gyrations. Based on the differences in each binder,there was some variation in the volumetrics obtained. The WMSA was ableto be compacted at 50° F.+ below the conventional mixture.

TABLE 20 Conclusion Summary (Warm Mix Asphalt Mixtures) PropertiesControl Blend No. 2 Blend No. 5 Design Gyrations 100 — — MixingTemperature, ° F. 311 250 250 Compaction Temperature, ° F. 291 240 240Percent Aggregate, Ps (%) 95.0 95.0 95.0 Percent Binder, Pb (%) 5.005.00 5.00 Gb 1.035 1.139 1.131 Gse 2.945 2.992 2.987 Gsb 2.871 2.8712.871 Pba 0.9 1.6 1.5 Pbe 4.1 3.5 3.5 P0.075 6.3 6.3 6.3 Gmm 2.695 2.7322.728 Gmb 2.593 2.606 2.582 Va, % 3.8 4.6 5.4 VMA 14.2 13.8 14.6 VFA73.3 66.5 63.2 DP 1.5 1.8 1.8

Based on the selection of Blend No. 2 (PG 64-28/20 wt. % Sulfur/0.5 wt.% PPA/3.5 wt. % Sasobit® wax) and Blend No. 5 (PG 64-22/20 wt. %Sulfur/0.5 wt. % Elvaloy® polymer/3.5 wt. % Sasobit® wax) severalasphalt mixtures were successfully prepared. During preparation of thebinder compositions used in the examples, essentially no H₂S wasdetected during the mixing or compaction process.

As indicated previously, the embodiments of the current inventioninclude a set of components in levels not previously used to develop andproduce a lower total material cost, high performance asphalt binderthat can also be used in warm mix asphalt applications. In hot mixasphalt applications, mixes are generally heated to 300° F. (149° C.) orgreater, depending mainly on the type of binder used. When asphalt mixescan be produced at temperatures of about 250° F. (121° C.) or lower itresults fuel cost savings and findings have shown that lower planttemperatures can lead to a 30 percent reduction in fuel energyconsumption. Thus, lower asphalt mixing temperatures also results inlower emissions, either visible or invisible, that may contribute tohealth, odor problems, or lower greenhouse gas emissions. The decreasein emissions potentially represents a significant cost savings,considering that 30-50 percent of overhead costs at an asphalt plant canbe attributed to emission control.

Further advantages of the present invention include the feature of thelow temperature reaction of sulfur and Elvaloy® polymer in asphaltbinders resulting in improved stiffness. Another advantage is thatpolyphosphoric acid and sulfur modified asphalt binders can be used toproduce a binder with reduced high temperature rotational viscositywithout reduction in the original dynamic shear properties. Furthermore,polyphosphoric acid and sulfur modified asphalt compounds can be used toproduce a binder with improved low temperature properties.

The addition of polyphosphoric acid and sulfur modified compounds, asused in embodiments of the present invention, provide improvedresistance to aging based on the Pressure Aging Vessel residue atvarious temperatures.

Embodiments of the present invention provide for the use of anysaturated polymer having backbone macromolecules (ethylene, propylene,butylenes, etc.) with macromolecular modifications (co-polymer,ter-polymer, graft-block co or ter-polymer (random, alternating, block,graft-block that can contain reactive functionality)) in a range ofabout 0 to about 5 wt. % in the presence of large loading of sulfur.Embodiments of the present invention also allow for the addition of asaturated polyolefin to a sulfur modified asphalt in the presence ofpolyphosphoric acid.

The use of Polyphosphoric acid and special fine crystalline long chainaliphatic hydrocarbons (such as Sasobit™ wax) in sulfur modified asphaltbinders in accordance with embodiments of the present invention allow abinder to be produced with reduced high temperature rotational viscositywith an increase in the Original Dynamic Shear properties.

The use of Polyphosphoric acid and special fine crystalline long chainaliphatic hydrocarbons (such as Sasobit™ wax) in sulfur modified asphaltbinders in accordance with embodiments of the present invention allow abinder to be produced with improved high temperature properties.

Embodiments of the present invention allow for the use of any saturatedpolyolefin (ethylene, propylene, butylenes, etc.) and saturated backbonemacromolecules (ethylene, propylene, butylenes, etc.) withmacromolecular modifications (co-polymer, ter-polymer, graft-block co orter-polymer (random, alternating, block, graft-block that can containreactive functionality)) in the presence of large loading of sulfur andSasobit® wax.

The binders developed in accordance with embodiments of the presentinvention have excellent flow properties at high temperatures forapplications in warm mix asphalts. These warm mix binders displayedsignificantly higher Performance Grades than the base PG 64-22 and noissues were observed in the preparation of the Warm Mix Asphalt.

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions, and alterations canbe made hereupon without departing from the principle and scope of theinvention. Accordingly, the scope of the present invention should bedetermined by the following claims and their appropriate legalequivalents.

The singular forms “a”, “an” and “the” include plural referents, unlessthe context clearly dictates otherwise.

Optional or optionally means that the subsequently described event orcircumstances may or may not occur. The description includes instanceswhere the event or circumstance occurs and instances where it does notoccur.

Ranges may be expressed herein as from about one particular value,and/or to about another particular value. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value and/or to the other particular value, along withall combinations within said range.

Throughout this application, where patents or publications arereferenced, the disclosures of these references in their entireties areintended to be incorporated by reference into this application, in orderto more fully describe the state of the art to which the inventionpertains, except when these reference contradict the statements madeherein.

That which is claimed is:
 1. A highly loaded sulfur-modified asphaltbinder composition for use with asphalt concrete for improved propertiesrelative to high temperature rotational viscosity without a reduction indynamic shear properties, the asphalt binder comprising: a. apolyphosphoric acid present in a range of up to 2 wt. % of the asphaltbinder composition; b. a macromolecular polymer having a saturatedbackbone with macromolecular modifications being present in a range upto 5 wt. % of the asphalt binder composition; c. sulfur, the sulfurbeing present in a range of about 20 wt. % to about 50 wt. % of thebinder composition, where the amount of sulfur being effective to atleast partially emulsify in the composition; d. non-surfactant additivesbased on wax chemistry being present in an amount sufficient to providea lubricating effect on the asphalt binder composition; and e. bitumen.2. The of the asphalt binder composition of claim 1 where thenon-surfactant additives based on wax chemistry is present in a range upto 10 wt. % of the asphalt binder composition.
 3. The of the asphaltbinder composition of claim 1 where the bitumen is present in a range of50 wt. % to 90 wt. % of the asphalt binder composition.
 4. The asphaltbinder composition of claim 1 where the asphalt binder composition has aDynamic Shear in a range of 1000 G*·sin δ to 5000 G*·sin δ at 28° C. 5.The asphalt binder composition of claim 1 where the sulfur is present inan amount of 20 wt. %, the polyphosphoric acid is present in an amountof 0.5 wt. % and the non-surfactant additives based on wax chemistry ispresent in an amount of 3.5 wt. % in the asphalt binder composition, andthe asphalt binder composition is PG graded as 64-28.
 6. The of theasphalt binder composition of claim 1 where the sulfur is present in anamount of 20 wt. %, the macromolecular polymer having the saturatedbackbone with macromolecular modifications is present in an amount of1.5 wt. % and the non-surfactant additives based on wax chemistry ispresent in an amount of 3.5 wt. % in the asphalt binder composition, andthe asphalt binder composition is PG graded as 64-22.
 7. The asphaltbinder of claim 1 where the asphalt binder has a rotational viscosity ina range of 0.100 Pa·s to 0.300 Pa·s at about 135° C.
 8. The asphaltbinder composition of claim 1 where the pressure aged residue of theasphalt binder has a Dynamic Shear in a range of 1000 kPa to 5000 kPa at22° C.
 9. The asphalt binder composition of claim 1 where the asphaltbinder has a rotational viscosity in a range of 0.100 Pa·s to 0.350 Pa·sat 135° C.
 10. The asphalt binder composition of claim 1 where theasphalt binder has a temperature effective range high temperature valuethat is greater than 80° C.
 11. The asphalt binder composition of claim1 where the asphalt binder has a Performance Grade of 82-16.
 12. Theasphalt binder composition of claim 1 where the asphalt binder has atemperature effective range that is greater than 99° C.
 13. The asphaltbinder composition of claim 1 where the asphalt binder comprises asphaltin an amount of 74.0 wt. %, sulfur in an amount of 20 wt. % and polymerin an amount of 1.5 wt. % of the asphalt binder composition, where theasphalt binder composition has a rotational viscosity that is greaterthan 0.300 Pa·s at 135° C., and where the asphalt binder has atemperature effective range that is greater than 100° C.
 14. A method ofpreparing an asphalt concrete composition having high sulfur load withimproved properties relative to high temperature rotational viscositywithout a reduction in dynamic shear properties, the method comprisingthe steps of: a. preparing an asphalt binder, where the asphalt bindercomprises: (1) a polyphosphoric acid present in an amount effective toincrease stiffness at lower mixing temperatures, (2) a macromolecularpolymer having a saturated backbone with macromolecular modificationspresent in an amount effective to increase viscosity of the compositionso that it can be used in warm mix applications, (3) sulfur present inloadings ranging from 20 wt. % to 50 wt. % of the asphalt binder, wherethe amount of sulfur is effective to at least partially emulsify in thecomposition, (4) non-surfactant additives based on wax chemistry, thenon-surfactant additives based on wax chemistry being present in anamount sufficient to provide a lubricating effect on the composition,and (5) bitumen; and b. combining the asphalt binder with aggregate suchthat the asphalt concrete is produced.
 15. The method of claim 14 wherethe non-surfactant additives based on wax chemistry is present in arange up to 10 wt. % of the asphalt binder.
 16. The method of claim 14where the bitumen is present in a range of 50 wt. % to 90 wt. % of theasphalt binder.
 17. The method of claim 14 where the aggregate and theasphalt binder are present in a ratio of 95 parts to 5 parts each byweight of the total of the asphalt concrete.
 18. The method of claim 14where the asphalt binder has a Dynamic Shear in a range of 1000 G*·sin δto 5000 G*·sin δ at 28° C.
 19. The method of claim 14 where the sulfuris present in an amount of 20 wt. %, the polyphosphoric acid is presentin an amount of 0.5 wt. % and the non-surfactant additives based on waxchemistry is present in an amount of 3.5 wt. % in the asphalt binder,and the asphalt binder is PG graded as 64-28.
 20. The method of claim 14where the sulfur is present in an amount of about 20 wt. %, themacromolecular polymer having a saturated backbone with macromolecularmodifications is present in an amount of about 1.5 wt. % and thenon-surfactant additives based on wax chemistry is present in an amountof about 3.5 wt. % in the asphalt binder, and the asphalt binder is PGgraded as 64-22.
 21. The method of claim 14 where the asphalt binder hasa rotational viscosity in a range of 0.100 Pa·s to 0.300 Pa·s at 135° C.22. The method of claim 14 where the pressure aged residue of theasphalt binder has a Dynamic Shear in a range of 1000 kPa to 5000 kPa at22° C.
 23. The method of claim 14 where the asphalt binder has arotational viscosity in a range of 0.100 Pa·s to 0.350 Pas at 135° C.24. The method of claim 14 where the asphalt binder has a temperatureeffective range high temperature value that is greater than 80° C. 25.The method of claim 14 where the asphalt binder has a Performance Gradeof 82-16.
 26. The method of claim 14 where the asphalt binder has atemperature effective range that is greater than 99° C.
 27. The methodof claim 14 where the asphalt binder comprises asphalt in an amount of74.0 wt. %, sulfur in an amount of 20 wt. %, and polymer being presentin an amount of 1.5 wt. % of the asphalt binder comprises, where theasphalt binder has a rotational viscosity that is greater than 0.300Pa·s at 135° C., and where the asphalt binder has a temperatureeffective range that is greater than 100° C.